Materials Outlook: Evaluating the Alternatives
A Scientist’s take on today’s green materials.
By Cynthia TylerSenior Research Scientist
Material ConneXion Inc.
Consumer packaging constitutes a significant percentage of household waste. As consumers become more aware of environmental issues, many are beginning to evaluate packaging materials.
Plastics are a ubiquitous packaging material for beauty products and require hundreds of years to break down in a landfill. Materials that offer disposal alternatives other than landfilling are important, especially when one considers that some U.S. states are running out of landfill capacity. According to the most recent data reported in 2004 by the National Solid Wastes Management Association, several states, including Alaska, Connecticut, Delaware, North Carolina, New Hampshire, and Rhode Island, are almost at landfill capacity. Other states, with New York leading the way, now send their trash across state lines for disposal. A 2007 Congressional Research Service Report for Congress noted that since 1995, interstate imports of waste have increased 147%, accounting for 42.2 million tons, or 25.3%, of municipal solid waste disposed in landfills or incinerators (excluding recycled or composted waste). Rather than build new landfills, we can look to bioplastics, along with other compostable and recyclable materials, to help decrease the amount of waste ending up in landfills.
In the past few years, advances in biotechnology and genetic engineering have enabled renewable agricultural crops to replace increasingly expensive oil- and natural gas–based plastic feedstocks. Polylactic acid (PLA), the most available bioplastic, is derived from corn, and its largest producer is NatureWorks LLC, now jointly owned by Cargill and Japanese chemical company Teijin Ltd. By composting the material under industrial conditions at higher temperatures and with mechanical aeration, the resulting compost can nourish the soil to grow more corn. PLA finds applications not only in single-use food and beverage containers, but also in durable goods including electronic devices, cell phones, and computers currently produced exclusively for the Japanese market—as well as cosmetics packaging.
When compounding bioplastics with additives (for example to impart color or improve strength), it is important to make sure that each additive is biodegradable and compostable, as verified by standardized tests. RENOL-natur color additive masterbatches from Clariant Masterbatches provide color to bioplastics and meet or exceed the European EN 13432 standard for proof of compostability of plastic products.
Make sure that all additives used on bioplastics are biodegradable and compostable. Clariant Masterbatches’ RENOL-natur color additive is a good example of such a product.
The colorants predominantly offered for use with bioplastics are synthetic materials, while RENOL-natur pigments are from natural, renewable sources, mainly plants. Available colors include red, orange, yellow, and green. (Blue is in the final stages of development.) Orange pigment comes from the root of the spice plant turmeric, and yellow is from flowers that grow in tropical regions like Brazil. The greens come from chlorophyll and other plant sources, while the cochineal insect is the source of natural red colorants. Additional shades and tones are possible by combining the colors.
Physical properties such as lightfastness (the degree to which dyes resist fading when exposed to light) don’t always measure up to nonrenewable pigments, so the bio pigments may not be suitable for all applications. Processing characteristics are similar to those associated with conventional masterbatches, and the resulting colors are earthy and organic looking, and some have excellent clarity.
There are some ecological drawbacks to using corn for the production of biopolymers. These include the use of land to grow corn, use of oil-derived fertilizers and pesticides, and greenhouse gas emissions from burning fuel to operate machinery during planting, harvesting, and transportation. The appropriation of farmland for nonfood use (compounded by the fact that even more land is used to produce biofuels), along with rising energy costs, have sparked an unintended consequence of higher food prices worldwide and, in some of the poorest nations, riots.
Similar to the efforts underway at biofuel companies, NatureWorks is addressing this land-use concern by exploring raw-material alternatives from nonfood plant sources to make the next generation of PLA. Some potential options include lignocellulosic agricultural waste such as wheat and rice straw, bagasse, and corn stover.
Since PLA will not break down in your backyard compost heap, the limited industrial composting infrastructure raises another concern about what happens when it is disposed of. If placed in a recycling bin by mistake, PLA can contaminate other plastics and downgrade their recycling potential. If, instead, it ends up in a landfill, a process similar to composting occurs, except in the absence of oxygen. In this scenario, anaerobic microorganisms break down the PLA and form biogas. This gas consists of carbon dioxide and methane—another greenhouse gas with 21 times the global warming potential of carbon dioxide. While some landfills collect biogas and use it as an alternative fuel to operate turbines that generate electricity, a small percentage of gas does manage to escape and enter the atmosphere.
Another end-of-life solution is closed-loop recycling. This offers both an alternative method of disposal and a renewable source of raw materials. The most common plastic recycling is by mechanical means, but this degrades the quality of the materials and limits further recyclability. Recently, manufacturers have been exploring methods of chemical recycling postconsumer plastics to create monomers for repolymerization. These polymers are of equal or higher quality than plastics from virgin materials.
Clothing brand Patagonia’s Common Threads recycling program uses a chemical recycling technology developed by Teijin. The closed-loop process breaks down old garments to create new polyester fibers, giving customers the opportunity to recycle their old clothing into new clothes.
Patagonia claims that, even when offset by the energy used to transport used garments from the United States to Japan, this process creates energy and CO₂ savings of 76% and 71%, respectively, when compared with the manufacture of virgin fibers. NatureWorks is developing a similar in-house recycling procedure for PLA regeneration with no loss of quality. The process chemically breaks down the PLA into the lactic acid monomer, available for repolymerization into new PLA resin. Closed-loop recycling is potentially infinite and offers a reduction in energy requirements and greenhouse gas emissions.
Another common material for beauty products packaging is paperboard. Although paper has one of the highest recycling rates, it may be recycled only a limited number of times. With each paper recycling iteration, the fibers become shorter, reducing the quality. The final life of recycled paper is usually toilet paper.
Unlike paper made from trees, TerraSkin, a biodegradable paper-like product made from calcium carbonate, can be recycled an infinite number of times, with no loss of quality.
New options are appearing for paper as well, however. TerraSkin is a treeless paper and can be infinitely recycled, with no loss of quality. According to Nicole Smith, environmental director at Chameleon Packaging, a division of Design & Source Productions and the manufacturer of TerraSkin, many retailers using the product for shopping bags have expressed interest in a take-back program that recycles the used bags into new bags—and gives the retailer an opportunity to reconnect with customers. Smith said that the firm intends to invest in recycling equipment after reaching an economy of scale. Until then, the treeless paper will degrade back into harmless minerals when left out in nature for approximately three to nine months.
Composed of calcium carbonate mineral powder (chalk) and a nontoxic resin, TerraSkin is water resistant and tear resistant. Some unique ecological manufacturing advantages over pulped paper include no water usage or resulting water pollutants, and no bleach required to achieve a bright white. Unlike fibrous paper that absorbs ink, TerraSkin requires 20 to 30% percent less ink for printing.
Materials are just one part of the sustainable-packaging equation. What happens to the packaging after its useful life is just as important, considering the disappearing landfill capacity. Not to mention, the inherent value of the materials lost in landfills or destroyed in incinerators is staggering when you think about the increasing raw-materials costs due to high oil and fuel prices and greater demand for resources from China and India. As an alternative, closed-loop recycling allows us to reclaim materials for infinite reuse.
Consumers are becoming weary of the proliferation of businesses using environmentalism as a marketing strategy, a condition known as “green fatigue.” Even worse, other companies are exaggerating environmental claims or “greenwashing.” Consumers care about the environment, and manufacturers have an opportunity win over these conscientious customers. One way is by taking a more comprehensive approach to sustainability by considering not just materials used in products and packaging, but also the environmental impacts of manufacturing and the end of life.
Cynthia Tyler, PhD, is a senior research scientist on the Advanced Material Solutions Team at Material ConneXion Inc. With a background in chemical engineering and materials science, she consults with clients on comprehensive, sustainable solutions that account for all stages of a product’s life cycle.
Material ConneXion has been at the forefront of sustainable-materials research since its inception in 1997. Subscription-based Material Libraries maintained in New York, Bangkok, Cologne, Daegu, and Milan contain more than 4500 advanced, innovative, and sustainable materials and processes. Since launching a partnership with McDonough Braungart Design Chemistry and the Environmental Protection Encouragement Agency in 2007, Material ConneXion has expanded its libraries to include cradle-to-cradle materials. Through its Advanced Material Solutions Team, the firm advises companies on how to implement cradle-to-cradle solutions.